No air flowing in climate control system.

How do I determine whether it is a blower motor problem or a resistor problem? Fuse is good and I checked power to the lead at the blower motor and have power on one of the two sides of the plug. Nothing fluctuates when I adjust the fan speed.

My car has 85000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
You could take a test light and disconnect the blower motor and connect the test light between the two wire connections and turn on a/c or heat and adjust the blower speeds to see if the light comes on and changes brightness when you adjust blower speeds on the controls. If you get a light then you need to replace the blower motor. If you get no light then you most likely have a blower resistor controller burned out and may also need to replace the blower motor since it most likely burned out the resistor.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

If your air handler is running but not blowing air, there are two likely scenarios; either a broken AC blower belt or an issue with the motor itself. If the air handler is humming or buzzing, but not making the mechanical sounds of a motor running, you`re most likely talking about an issue with the motor itself.
There can be a number of reasons why you can air conditioning is not blowing cold air. The most common reasons could be a clogged filter, cooling fan problem, radiator trouble, or it could simply be that you need to recharge (regas) your air conditioning.
Nine times out of 10, weak airflow is caused by a clogged up cabin air filter. Over time, this filter catches all dirt and debris, which can build up and slow or stop the flow of air. It`s typically located under the dash on the passenger side or inside the glove box and should be cleaned or replaced regularly.
If the heater isn`t blowing hot air at you when you turn the system on, the blower fan might have a problem. Either it`s not getting electrical power or, more likely, the motor itself has simply burned out. A blower motor in an older vehicle is likely to burn out over time, and may need replacement.
* If your HVAC is running but NO air is blowing through the vents, check the filter. If it`s clogged, replace it. You should be replacing the filter on a regular schedule.
An air blower uses a rotating impeller/rotor to create a vacuum. This vacuum causes air to rush into the blower. The air enters the centre of the impeller and is divided by the rotating blades. Centrifugal force increases the speed of the air and volume of the air stream within the housing.
The blower motor relay is the electrical switch that is used to supply the power for the vehicle`s blower motor. The blower motor is the component responsible for pushing air through the vents of your vehicle`s heating and air conditioning systems.
Weak airflow can happen due to several reasons like a clogged air filter, blocked vents, accumulation of debris around the outdoor unit, leaking ducts, low refrigerant level, fan problems, etc.
The Filter Is Clogged

In some cases, the buildup of dust and debris can thicken to the point where the passage of warm air is blocked by the filter. Therefore, while it might seem as though the furnace is not blowing air, the only real problem is that the furnace needs a new filter.

Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.
Check the Filters and the Vents

Blower motors are designed to circulate air, so they won`t work if there`s no air to move. You should always check the filters and vents surrounding the blower to make sure that the blower isn`t having a hard time working.

The blower motor is responsible for sending air through the vents of your car. Over time, blower motors can become damaged, or completely fail. In which case, air will no longer come out of your vents.
Blower resistors are resistors which are used to control the fan speed of automotive blowers. The fan speed can be changed either by switching the blower resistor resistance mechanically using a rotating lever, or electronically by the air conditioning system.
The most common airflow control strategy for centrifugal fans is the outlet damper. Sitting right on the outlet of the fan, this is an opposed blade-style outlet damper. We control the flow by incrementally closing the blades to reduce the airflow volume while raising static pressure.
Electric fans have a motor that turns a shaft on which there is an impeller. The turning impeller creates air pressure, causing air flow.
The main reason for a clogged milk duct is inflammation in the tissue and blood vessels surrounding the milk ducts, which can happen for a variety of reasons: Skipping feedings or pumping sessions or going too long between feedings. Changing your baby`s feeding schedule (like during weaning or starting solid foods).
What Does The Blower Motor Do? The blower motor controls the airflow for the heating and cooling system; it is one of the main components for the HVAC system to operate properly. The blower motor turns on the fan in your HVAC system, allowing the air to circulate out of the system and into the rooms of your home.
Look for it first around on the exterior of your machine, especially along the bottom edge near the ground. An AC`s reset button is typically red and visible, so it should be easy to spot. If you don`t see a reset button on the outside, it could be located inside the unit behind the service panel.
The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.
We do suggest that you replace the resistor at the same time. It may not be critical, but this will keep the system more uniform. The issue may even be related to the resistor. If you know that it is not related to the issue, then you do not have to replace it.
Problems like a fan clogged with dirt, a dead motor, a loose fan belt or a stuck wheel can all cause your blower to not work properly. These problems can keep the blower fan from blowing enough air out of your vents to keep you cool. Your evaporator coil needs air to blow over it to complete your AC`s cooling process.
If your leaf blower does not blow air, it is possible that debris has been sucked into the blower housing, impeding the impeller from doing its job. If the impeller is loose or the blades of the impeller are damaged or broken off, it can also cause the blower to become unable to blow air.
If the hum occurs when the motor is on but not turning, the capacitor may be damaged and, if so, should be replaced. This could result from a poor quality capacitor or a blocked filter. Humming when the blower is off usually indicates that the pilot light needs to be readjusted to the appropriate level.
Problems like a fan clogged with dirt, a dead motor, a loose fan belt or a stuck wheel can all cause your blower to not work properly. These problems can keep the blower fan from blowing enough air out of your vents to keep you cool. Your evaporator coil needs air to blow over it to complete your AC`s cooling process.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Why is my air system blowing out hot air in spurts and why is the temperature gauge nearing hot while in use?
ANSWER : This can be caused for a variety of reasons such as a malfunctioning thermostat, a radiator not flowing properly, a faulty coolant temp sensor or AC refrigerant not properly being supplied to the AC compressor. Your car’s AC system puts a heavy strain on your car’s engine when it runs as it requires a lot of power to run. When the AC compressor comes on it puts additional strain on the motor that may be already struggling to stay cool as a result of any of the issues named above. I would recommend having an expert from YourMechanic come to your home to diagnose and repair.

Hot air mixed with cold blows from air conditioning
ANSWER : Hey there. You will most likely have to have a mechanic bypass the heater coolant lines to have this resolved. Your A/C may not be controlling the air flow inside the evaporator correctly out of the vents and may be the blend door actuator stuck in the heat position. Have the AC system diagnosed first before bypassing the heater.

The climatic control is on one temperature all the time hot on drivers side cooler on passanger side the flap control moter for ho
ANSWER : A temp sensor malfunction could be causing your problem. If the controller is getting bad information, it’s going to operate the doors according to that information. So a sensor replacement is indicated. However, these systems can also have problems with the stepper motors themselves that drive the flaps. All the little plastic gears can get jammed up. In most cases, the self diagnostics will catch that and give you a code, but not always. If you have the right scan tool, you should be able to activate the motors and watch them work. Working on the climate control can be difficult and time consuming, if you want to have the job taken care of for you, contact YourMechanic and they’ll send a technician to your home or office to diagnose your climate control issues and advise you as to what to do about it.

’08 Nav Needing Air Suspension Help
ANSWER : It is possible that you could have a restriction in the line that goes from the compressor to the rear air spring. This resriction would prevent the air from reaching the air spring. I would recommend dis connecting the line at the compressor and at the air bag and shooting compressed air through the line to make sure it is not restricted. If something comes out of the line, you should be able to reconnect the lines and the air suspension system should work properly again.

Trying to locate the Mass Air Flow sensor , and the Idle Air Control valve 2002 Ford Fiesta
ANSWER : Hello – Mass Air Flow meter is a short, cylindrical section of the air intake, just inside of the air filter housing, and just before a large cuved plastic-molded piece of the air intake. It has a flat electrical connector plugged into it. The idle air control valve is just past the throttle body in the intake, on the engine side of the throttle body. It is a small cylindrical tube about 1 1/2: in diameter and 4 inches long, bolted to the intake manifold with an electrical connector. For the effects of dirty sensors – click here.

Evaporative Emission Control System Purge Control Valve Circuit Malfunction how to fix and where is it ?
ANSWER : Hi there. The best advice I can offer is for you to complete one of two things. First, it would probably be best to have a professional mobile mechanic come to your location and complete a check engine light inspection so they can pinpoint what part of the EVAP system is causing your failed emissions test. If you decide you want to do this on your own, then it would be a good idea to purchase a service and repair manual for your Ford Mustang – so you can look at detailed diagrams and replacement instructions.

My car’s air conditioning/heating system only works for a brief time and blows the wrong temperature air
ANSWER : Your Villager comes equipped with either an automatic climate control system or a manual controlled climate system. The automatic controlled system uses four separate sensors and as many modules to operate. Any of these can be the source of the symptoms you are experiencing.

With your symptoms, I tend to think you have an automatic system. If this is the case, you will need a shop level scanner to access the vehicle climate control data. Without access to this data, repairing your system will be guessing.

When it comes to a manual system, it only changes in that there aren’t any sensors to allow the computer to determine what to do. The diagnosis is virtually the same. When it comes to the blower motor tuning off after ten or so minutes, this is most likely the same component that is causing the temperature settings to be incorrect.

Because of the complicated nature of these systems, I recommend having a professional mechanic, such as one from YourMechanic, perform an inspection in order to diagnose the precise nature of the AC/heating problem.

Does non-climate control car AC cut-in & cut-off automatically?
ANSWER : A/C systems that used fixed displacement compressors will cycle on and off (the compressor that is) depending on cooling demand. If you have a variable displacement compressor in your vehicle, though, the compressor may hardly ever cycle simply because the compressor is capable of load following. In fixed displacement systems, without automatic climate control, the rate of cycling is usually determined by pressures within the system. An example of this type of system is what’s known as a CCOT (cycling clutch orifice tube) system. The compressor clutch will cycle on and off depending on cooling demand, usually at around 21-23 psi on the suction side, but of course there is variance from car model to car model. On newer car, the vehicle’s PCM is involved in the control strategy, too, as the PCM can command the compressor off during periods of high engine demand, such as rapid acceleration. Insofar as climate control heating and HVAC systems, those are electronically controlled and, in the main, merely "automate" all the mechanical controls that formerly were used to control the position of blend doors and the heater control valve. Control strategies are electronics-based. If you need a diagnostic of a vehicle HVAC problem, performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request HVAC inspection/testing and the responding certified mechanic will address your issue(s). If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.